Optical spectra and laser action in Nd3+-doped CaY2Mg2Ge3O12

Crystals of the garnet-structured germanate CaY2Mg2Ge3O12 have been grown from a melt containing 6 mole% Nd3+. The fluorescence, absorption, excitation spectra, lifetime, and linewidths have been measured and were compared with the results for Nd3+:YAG. The important spectroscopic features of Nd3+:CaY2Mg2Ge3O12 are a lifetime of 305 μsec, a strong absorption in the near infrared, a very intense fluorescence line at 941 nm, and a linewidth at this wavelength of approximately 37 cm−1. Laser action has been achieved at 1058.96 nm at room temperature. An estimate of the laser transition cross section gives a value of σ=6×10−20 cm2.